A better solution than /wd4996 to disable "depreciated posix" garbage.

This solution doesn't emit warnings under VC 6.

Backport: 567523

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@567524 13f79535-47bb-0310-9956-ffa450edef68